Ratalang Basham Beach Coastal Dune Adaptation

The challenge

Ratalang (Basham Beach) sits on the Fleurieu Peninsula, where the foredunes are the main protection for the low lying conservation reserve behind them. Recent storms cut into the dunes, and beach monitoring showed a shoreline that was losing sand and not recovering naturally. Alexandrina Council engaged Magryn to understand how much of the dune and reserve was at risk, over what timeframe, and what could be done about it.

Our approach

We built a baseline from site inspection, survey and sediment sampling, and compared it with earlier records to see where sand had gone and how quickly. Coastal modelling then tested how the dune responds to storms and to a changing coast over the coming decades. Those findings fed directly into the design, so the adaptation options are shaped by how the shoreline is expected to behave. Each option was weighed on coastal protection performance, constructability, maintenance and environmental and social impact.

The outcome

The assessment gives Alexandrina Council a clear picture of how the shoreline is likely to change and which sections need attention first. It sets out a range of dune adaptation concepts, from re-establishing the dune through to hybrid, nature-based approaches, with a staged pathway so Council can act ahead of coming storm seasons while the longer term solution is refined. For Ratalang, that gives the conservation reserve, its habitat and its public beach access an evidence led way to keep protecting the coast as conditions change.